Do you think New Zealand summers are too mild to be concerned about your roof colour? Think again. According to BRANZ research, 70% of Kiwi households feel their houses are too warm in the summer, and this number is increasing year after year. What is the good news? One of the most intelligent things you can do is also one of the simplest: Select the appropriate roof colour.
How Roof Colour Affects Your Home’s Temperature
Your roof is the largest surface directly exposed to New Zealand’s hot sun. When sunlight hits a dark surface, it’s absorbed as heat. When it hits a lighter surface, much of it bounces back. This is known as Total Solar Reflectance, the higher the percentage, the cooler the roof.
According to the NZ Metal Roofing Manufacturers’ Code of Practice, an insulated dark-coloured roof is capable of reaching temperature levels of over 80°C, but an insulated light-coloured roof can reach around 60°C under the same conditions. That 20°C surface difference is directly reflected in roof cavity temperatures and eventually in your living rooms.
The Best Colorsteel Colours for Heat Reflection
Colorsteel® is New Zealand’s top roofing steel, and its technical data simplifies colour choosing. Here are the top achievers according to TSR:
| Colour | TSR % | LRV % |
| Cloud | 72 | 76 |
| Titania | 67 | 69 |
| Desert Sand | 58 | 51 |
| Gull Grey | 57 | 50 |
Read more at https://www.colorsteel.co.nz/assets/Brochures/ColorSteel_Reflectivity_4pp-June2020.pdf
By contrast, some of NZ’s most popular dark colours, Ironsand (25%), Anthracite (21%), and Ebony (7%), absorb the vast majority of heat that hits them.
If you’re planning a re-roof and want to reduce summer heat gain, lighter shades are the clearest path forward. Explore the full colour range on our website.
Why This Matters More in NZ Than You Might Think
UV radiation in New Zealand is roughly 40% more powerful than at similar Northern Hemisphere latitudes. Aucklanders are exposed to around 137 days of very high or intense UV radiation per year.
When combined with New Zealand’s warmer summers, this level of intensity has severe consequences. BRANZ data shows that indoor summer temperatures have climbed by 1.3-2.1°C over the last 20 years, with 36% of bedrooms being categorised as overheated.
More Kiwis now complain about being too hot in the summer than being too cold in winter, which is reversing an ancient pattern.
What If You Prefer a Darker Roof Colour?
Many Auckland communities prefer darker roof colours.
Resene CoolColour™ replaces traditional black pigment with an infrared-reflective alternative. The finish looks identical to a typical dark colour, and it generates less heat for only around 10% more money.
The most effective approach combines colour selection with R6.6 ceiling insulation (now required by NZ Building Code H1), enough roof ventilation, and proper eave overhangs. Colour alone will not carry the load, but it is a significant part of the equation.
Ready to Choose the Right Roof for Your Home?
Since 1998, Advance Roofing has helped Auckland residents make smart roofing choices. As licensed building practitioners our team can assist you with colour choices, material options, and installation, all backed by a 5-year workmanship warranty.
If you are thinking about re-roofing in Auckland, and it’s the time to choose a roof colour get in touch! We work with Colorsteel and long-run roofing profiles such as Corrugate, Styleline, and Dimondek, providing you a wide selection of performance and appearance options.
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